The term biochemical can refer to any chemical compound which is part of the makeup of living cells. The major biochemicals which Worthington purifies are proteins obtained from materials such as beef pancreas, plant, and fermentation sources and other natural substances.
Enzymes are proteins which act as catalysts. Every aspect of life involves chemical reactions. When you eat, starches are broken down into simple sugars; proteins which may come from meat or eggs break down into the simple amino acids which make up the protein. None of these reactions happen spontaneously in your body. Catalysts are needed to get each kind of reaction going, and enzymes are the catalysts used by living organisms.
Enzymes are used in medical research. An example is the use of an enzyme called collagenase for dissolving tissue. All of the cells of any organ are held together by a protein called collagen. If a scientist wishes to study one particular kind of cell, he can take a sample of tissue, soak it in a solution of the enzyme collagenase, and after some period of time all of the cells will separate from one another, but each cell will still be alive and functioning. Now the scientist can 'plant' one of the individual cells in a petri dish and add some nutrient. If the selected cell has not been damaged, it will divide over and over until new tissue has formed made up of many copies of the original cell. This operation is called 'tissue culture'.